Telegraph repeater



Patented June 30, 1933 who SYRU'S FERGUSON, OF NEW YORK,"N. Y.,

GRAPH COLIPANY, OF NEW YORK, N

ASSIGNOR'TO THE WESTERN UNION TELE- Y., A CORORATION OF NEW YORK TELEGRAPH REPEATER Application filed March 26, 1930. Serial No. 439,125.

This invention relates to a telegraph system and more parti ularly to a repeater oi the single line or duplex halt repeater type. It is especially advantageous in connection with telegraph systems having large electrostatic rapaeit and em;)loyingnuu'hiue transmitting and receiving apparatus operating at a high speed. although it not limited thereto.

ln printing telegraph systems as ('om monl emplored. the signals are transmitt d in accordance with a fire or six unit code composed of combination of marking and sparing impulses. The. signals may be transmitted thiongh the keyboard of a printing machine or by a tape transmitter or other form of storage transmitter and the sparing and marking impulses comprising each signal train are transmitted at a predetermined speed and are of substantially equal duration. The printing mechanism operates in \'nrhr u|isni with the transmitting appara tns and responds to each signal combination to ell'ert the printing of a particular chararter.

The speed ol operation of such machines requires the transmission of the individual impulses at a higher frequency than ordinarily employed for manual signalling, and at such speeds only a limited and definite time is available for the marking and spacing impulses to accomplish their function. Any distortion at the signals. such as the lapping over of" a marking signal into the period allotted to a spacing signal. or the shortening of eith r sparing or marking signals. or an out-ot-phase coijnlition thereof, ma cause the improper operation of the printing I'HQt'llHHlSII].

However, in av single line circuit; the speed of transmission of telegraph signals over lines having considerable electrostatic ea: nacitv is limited, because of the time occupied in charging and discharging the line. During the time the line circuit. is closed and potential is applied thereto at the transmit-- ting station. tor transmitting a marking signal, the line accumulates an electrostatic charge, thus delaying the building up of the operating current at the receiving apparatus.

Similarly. upon opening of the line atthe iltlllfilllllllllg station. to transmit a spacing; signal. the charge preriouslv art-umulatwl n the line must dis lmrge through the re iving end thereot. and eouserpi ntlv. the lion ot' tilnl'ttlltlg' enrrent through the receiving apparatus 1\ prolonged. In lines having large rapaeitr. the time required to disrharge the line to the potential of the rec iving terminal or down to the operating le\'el of the reweiving apparatus. mar tend the pr vi us marking signal over into the sparing in rval so as to ronsiderahlr lengthen the marking signals and eorrespoin l ngly shorten the spacing signals.

-\ssuniing the line to be of unite-rm ("a parity. the electrostatic charge along the line during the time that potential applied at one end thereof is not uniform ut is directlr proportional to the voltage at *ach particular point and. therefore. in a line having the potential applied at the transmitting end. the charge is very nun-h greater at such end than at the receiving end. As a eonsequence. a longer time is required to discharge the line through the receiving and than would he required if the line were unifornilv eharged.

this effect of capacity on telegraph circuits has long been appreciated, particular-Iv 1n submarine telegraph cables, and it has heeii the practice, therefore. to ground the cable at the transmitting end fora brief interval between signals to permit the'line, at the pla e n'herc the charge is maximum. to discharge quickly in the direction of the transmitting end, in order to reduce the effect of the discharge current on the receiving apparatus,

It is one of the objects of the present in vention to apply this principle to single lin and duplex half repeaters and to provide i repeater for use with a single line circuit i which the opposite ends of the outgoing li e Will be subjected to the same potential at tho imminenrementot aspacing signal, and th line thus discharged mainly through lllt transmitting end. The discharge current. therefore, is di erted away from the I'eeel ing instrument to a large extent and the Hi to of discharge of the line to the operating level of the receiving apparatus is increased.

Another objectis to provide, in a single line or duplex-half repeater, an improved locking arrangement for preventing the repetition of spacing signals back over the line from which they are .being received.

Other objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings and appended claims.

In accordance with my invention I provide a telegraph re eater, either of the single line or dupleX-hal repeater type, utilizing either a single current or biased polar relay in the single line circuit, the relay having an operating and a locking winding. The circuit for the operating winding, when marking signals are being transmitted, is completed from a source of current to the outgoing line through the tongue and marking contact of the opposite line relay, the distant end of the line being grounded or of definite potential. The locking winding of the relay is short circuited at this time through the tongue and marking contact of the opposite line relay. The arrangement of the relay windings is such that when the tongue of one relay leaves its marking contact, in response to a spacing signal, the circuit including the operating winding of the other relay is completed through the locking windin" thereof, in a marking direction and thence directly to the outgoing line, the resistance of this circuit being sufficiently high to effect an initial reduction in the outgoing line current at the beginning of the spacing signal, that is, during the travel time of the relay tongue to its spacing contact, and upon engagement of the relay tongue with its spacing contact, the locking circuit is completed through the spacing contact directly to ound or to a source ofdefinite potential.

he spacing contact at the same time applies to the outgoing line, a source of potential of the same polarity and magnitude as that applied at the opposite end of the line. Prefgrably, I ground each end of the outgoing Since the opposite ends of the line at this time are at the same potential and form part of a closed circuit, the line discharges rapidly from electrostatic effects and mainly in the direction of the transmitting end thereof. The spacing signal is therefore repeated, of substantially full duration and the outgoing line is placed in a discharged condition to respond quickly to the succeeding marking si nal.

11 order that the invention; may be more fully understood, reference willbe had to the accompanying drawings in which the single figure is a circuit diagram of a single line repeater embodying my invention.

In the drawing, I have shown a repeater connected to a source comprising a polarized line relay LR and a polarrzed me relay LE each having a biasmg winding 1, an operating winding 2, and a locking winding 3. The biasing windings 1 each have a grounded source of current 4, such as a generator, connected to one terminal thereof, the opposite terminal being grounded at 5, the polarity of the current source 4 being such as to bias thetongues T of the relays towards their spacing contacts S. One terminal of each of the operating windings 2, is also connected to a grounded source of current 6, the opposite terminal of the winding. of relay LR being connected by a conductor 7 to the marking contact M of relay LR The corresponding terminal of the winding 2 of relay LR is connected by a conductor 8 to the marking contact of relay LR The locking winding 8 of relay LR, has one terminal connected, through the resistance R to one end of the operating winding 2, the opposite terminal of the locking winding being connected to the tongue T of relay LE Likewise, the locking winding 3 of relay LE has one terminal connected through the resistance R to the one terminal of the operating winding 2, the opposite end of the locking windin being connected to the tongue of relay R The spacing contact of each of the relays is grounded at G The tongue of relay LR is also connected to the outgoing line L which is provided at the distant station A, with a printing apparatus P The printing apparatus may include an operating magnet 10 and a group of transmitting contacts 11, one terminal of the latter being grounded at G The circuit through the transmitting contacts, when the printer is on the receiving end of the line, is completed through the normally closed contact 13.

Similarly, the tongue of the relay LR is connected to the line L, which terminates at the distant station B, in a simplex printer P The operation of the system is as follows: F11

With both printers idle and the contacts 13 closed, a circuit is completed from each of the sources of potential 6 through the opcrating windings 2 and marking contact and tongue of the opposite relay, to the lines L and L and thence through the contacts of the printing mechanism to the ground. The tongues of each of the relays are thus held on their marking contacts against the biasing eiiect of the windings 1. If the transmitting contacts 11 of the printer P at station A are opened, to transmit a spacing signal over the line L, the current in the operating winding 2 of relay LE falls to zero and the tongue of the relay LR leaves its marking contact, due to the spacing bias produced by the winding 1. The circuit of the operating winding 2 of relay LE is thus ICI broken at the marking contact of relay LE I relay of the locking winding 3 is also broken at the marking contact of relay LR As a consequence, current flows from the source of current 6 to the operating winding 2 of relay R in a marking direction, resistance R and locking winding 3 in a marking direction, directly to the line L Due to the resistance R the current in the line L is reduced in magnitude. However, since this reduced current flows through the additional windings 3 of relay LR it exerts a suflicient magnetizing force on therelay LR to maintain the tongue of the contact. At the time the tongue of the relay LR reaches its spacing contact, ground G is applied directly to the locking circuit and at the same time, the ground G is also applied to the line L, the line L being thus grounded at both ends rapidly discharges.

It will be understood that in place of grounding each end of the line L, a source of current of the same polarity and strength might be applied to each end of the line and the same rapid discharge of the line obtained.

While a single locking winding has been shown for relays LR and LE it is to be understood that a number of locking windings maybe employed in addition to the operating winding and the number of turns thereof may be pro ortioned so that the ampere turns provi ed when the locking windings are in circuit with the ground G is substantially equal to the ampere turns provided when the operating windings 2 are directly in circuit with the lines L and L In order-that the appended claims may be readily applied to the embodiments of the invention shown, the line L may be considered the incoming line, relay LR being the receiving relay and relay LR the transmitting relay for this line. It is to be understood, however, that the repeater provides for transmission of signals in either direction.

Various modifications and changes in the circuit arrangement may obviously be made without departing from the invention and, therefore, I do not desire to be limited to the exact arrangement illustrated and described except in accordance with the appended claims.

What I claim is:

1. In a signaling'system, a line circuit, a receiving relay and a transmitting rela} associated therewith, said transmitting relay being in an outgoing line circuit controlled by said receiving relay, means for maintaining a closed circuit through the operating winding of said transmitting relay and said outgoing line when the tongue of said receiving is. on one of its contacts, means for reducing the current in said outgoing line when said tongue is away from both of its contacts and means for establishing a circuit forthe winding of said transmitting relay, inderelay upon its marking pendently of said outgoing line and producing a unipotential condition for the opposite ends of said outgoing line when the tongue of said receiving relay is on its other contact.

2. In a signaling system, a line circuit, a

receiving relay and a transmitting relay associated therewith, said transmitting relay being in an outgoing line circuit controlled by said receiving relay, means for maintaining a closed circuit through the operating winding of said transmitting relay and said outgoing line when the tongue of said receiving relay is on one of its contacts and means for establishing a circuit for the operating winding of said transmitting relay, independently of said outgoing line .ind n'odncing a unipotential condition for the opposite ends of said outgoing line when the tongue of said receiving relay is on its other contact.

3. In a signaling system, a line circuit, a receiving relay and a transmitting relay associated therewith, said transmitting relay having a winding disposed in an outgoing line circuit controlled by said receiving relay, means for maintaining a closed circuit through said outging line when the tongue of said receivingrelay is on. one of its contacts, and means for producing a unipotential condition for the opposite cnds'ot said outgoing line when the tongue ol' said rcceiving relay is on its other contact.

4. In a signaling system. a line circuit, a receiving relay and a transmitting relay associated therewith, said tran m tting relay having an operaiin indii a locking 2 being in a winding, said opcrziting winoi normally closed circuit including one contact of said receiving relay and said operating and locking windings being in a eparate circuit including the other (:01 act of said receiving relay, the resistanu. rid second circuit being greater than that of the first circuit, and the windingsoi said transmitting relay being proportioned so that the ampere turns will be substantially uniform when the tongue of said receiving relay is on either of its contacts.

5. A repeater having an J m-inning line relay and an outgoing line iy, the incoming line relay repeating to outgoing line and the outgoing line relay repeating to the incoming line, an operating winding for said outgoing line relay, the circuit for said operating winding being normally closed through the marking contact of the incoming line relay, to the outgoing line, said circuit being completed dur g the transmission of spacing signals o, r said incomingli'ne through the spacing coWact of said incoming line relay indepen' lily of said outgoing line, and said circuit being completed during the time the tongue of said iii-- coming line relay is away from its contacts, directly through the outgoing line.

6. A repeater having an incoming lay and an outgoing line relay. the incoming line relay repeat-ing to the outgoing line and the outgoing line relay repeating to the incoming line. an operating winding and a locking winding for said outgoing line relay, the circuit for said operating winding being normally completed through the marl;- ing contact of the incoming line relay. to the outgoing line, said circuit being conipleted during the transmission of spacing signals over said incoming line through the locking winding and spacing contact of said incoming line relay independently of the outgoi ig line. and said circuit heing completed during the time the tongue of the incoming line rela is away trom its contact, directly through the locking winding and said outgoing line.

7. A telegraph system comprising a repeater having an incoming and an outgoing line. associated therewith. a ielay for repeating signals tran n'iitting over the incoming line. to the outgoing line. means including the contacts of said relay for maintaining a closed circuit through said outgoing line when marking signals ar transmitted over said incoming line, and means acting when spacing signals are transmitted over said incoming line to first reduce the current in said outgoing line. and suhsequently. to connect both ends of said line to potential of the same magnitude and polarity.

8. A telegraph repeater having an incoming-line relay and an outgoing line relay. an operating winding for said outgoing relay. the circuit for said operating winding heiug completed through the markingconta t of said incoming line relay and the outgoing line, when marking signalsare transmitted over said incon'iing line. said circuit heing completed through the spacing contact of said incoming line relay when spacing sis!- nals are heing received. and said circuit lieing completed to the outgoing line independently of said contacts during the travel time of the tongue of said inroining line relay from one of its contacts to the other.

9. A telegraph repeater having an incoming line relay and an outgoing line relay. an operating and a locking winding for said outgoing line relay. the circuit for said operating winding being completed directly through the outgoing line when marking signals are lreing transmitted to said incoming line relay. said circuitv heing eon'iple'ted through said locking winding when the. tongue of said incoming line relay is away from its marking contact. and means for connecting the end of said outgoing line, at the repeater. to a potential of the same polarity and magnitude as the distant end of the line, when the tongue of the incoming line relay engages its spacing contact.

In testimony whereof I atlix my signature.

CYRUS C. FERGUSON. 

